How to select image object instead of group

[Scott Pepperdine]

I have an image object that is part of a background group, so when I 
create a new card, there it is along with a number of other fields.
But when I click the image object, its script is not activated, but 
rather the script of the group it belongs to.
What do I need to study to make the image selectable?

Thanks very much,
--Scott